Valve for rock drills



v 1 621 254 March e. w. HULSHIZER VALVE FOR ROCK DRILLS Filed Dec. 1'7, 1925 cylinder during a portionof the stroke of' the piston and by constantly exposing the Patented Mar. 15, 1927. r

UNITED STATES PATENT caries;

GEORGE W. HULSHIZEB, OF STEW'AR'ISV'lILI Ill,'NEHJERSEY ASSIGNOR 'IO INGERSOLL- V RAND COMPANY, OF. JERSEY CITY, NEW JERSEY, A CORPQRATION OF NEW. JERSEY.

VALVE FOB ROCKDRILLS Application filed December 17, 1925. Serial No. 76,016.

This invention relatesto'rock drills, but more'particularly tea-distributing valve of the spool type for fluid actuated rock drills.

' The objects of this invention-are to improve generally valves of this type and to obtain a quick and positive valve action by relieving'compression from the ends of the ends of the valve to live pressure fluid. 7 Other "objects will be inpart obvious andin part pointed out hereinafter. I V

' Thejinvention consists of the combinations of elements, features of construction and arrangement of parts having the general mode of operation subst-antiallvfas hereinafter described and more particularly pointp in the accompanying drawings, inwhich ed out in the appended claims and illustrated I t Figure :1 is a view in elevation partly in sectlon of a portion of a'rock drill show ng the valve 1n positlon for admitting. pressure fluid to the rearward end-of the cylinder for 'impelling the piston forwardly, and V Figure.2 is a View similar to Figure 1 illustrating the position 'of the Valvefor ad- 7 mittingpressure' fluid to the front end of a rock drill having a' cylinder Alwhich in the cylinder to return the piston.

Referring more particularly to the draw-Y ,ings, theinvention-is shown'embodiedin J v escape of a portion of the atmospheric; air entrapped in the cylinder ends by the ham- 1 this instance is provided'with a free exhaust 7 port B. f Within thecylinder A is a reciprocatory hammer piston C having a forward extens1on or nose D which cooperates slidably with a front cyhnder washer E seated in the front end of the cylinder A to form aclosure therefor. The rearward end ofthe cylinder Ads in this instance sealed by a closure F. a v v I V TheclosureF is shown solid and the nose D of thepiston C is shown as a plain exten-' sion forv the sake of simplicity ofillustration.

In the present instance avalve chest G having a chamber-H is arranged longitudinally of the cylinder A and has an finlet p I I distributing valve 6 having a longitudinal connection J for the admis'sion of pressure fluid to the chambenI-l from'a source of pressure fluid supply. The valve "chest G may be eithervformed integrallyfwitlrthe cylinder A or may be formedseparately'as indicated in the drawings and secured in position inany suitable manner as for 'in-' respectively.

The chamber H is in thisinstance of uniform diameter throughout' 'its length and is open at its ends to receive sealing 'plugs-K and L. The plugs K and L are provided with central bores O to receive a-bolteP' 1 "provided with a suitable nut Q wherebythe plugs K and L may be held securely'in be of any suitableform. In-the present instance the passages are'of smaller area at" the point of communication with theinlet connectlon J and are flared toward their outer, ends at which point they open to a height approximately equal to the diameter of the ports '1 and U. Leading from the ports T andU tothe front and'rear ends of the chamber H are reduced passages W and 7X through which live pressure fluid may constantly flow tothe ends ofthe chamber Means are provided for permitting the Iner piston C. To this end compression is lief passages Y and Z are formed tolead from the front and rear ends of the cyllnder 1y of the vertical center of the chamber H; In like manner, the passage Y communicating with the front end of the cylinder coinmunicates with a point in the chamber H of the vertical center of Q said rearwardly chamber.

" Within the chamberH i s a pressure fluid bore a which cooperates slidably with th bolt The valve. 7) is of the spooltype' and which control the admission ofpressure fluid from theports T and Uto' thefront and I rearward end of the cylinder.

rear ends of the cylinder respectively are prov1ded with actuatlng faces 7 and it respectively against which pressure fluid may constantly act to assist in throwing the valve in a manner to be hereinafter described.

The travel of the valve Z) is in this instance limited by the stops Kand I1 against which the actuating faces g and hot the valve may strike. r

Leading from the chamber II from a point intermediatethe inlet connection .I- and the 'port T is a passage 7' for exhausting entrapped atmospheric air admitted into the chamber H through the passage Z from the A similar exhaust'passagek is formed between the inlet -.-position pressure fluid will flow through the connection Jand the port U for relieving compression in the front cndjof thej cyhnj der A;

- In the operation ;of the drill, with the valveb in the position indicated 1n Figure 1,-the port U will be uncovered by the hea'd .f' of the valve. WVhen the valve is in this passage Y and theport Il into the rearward end of the chamber II and through the inplet passage S to the rearward end of the cylinder A and impel the piston forwardly. After the piston C covers the fre-eexhaust ,port B, a portion of the atmospherlc air entrapped in the forward end of the cylinder will be exhausted through the passage Y; into the chamber H between the valve heads; and c l, from whence it will pass through the passage 70 to the atmosphere.

As the piston C continues on its forward stroke, the said piston will cover the passage 7' Y and during the remainder of its stroke, the remalnlng portion of atmospheric air in the front end of the cylinder will becompressed and passing through the passage R will act against the actuating face 9 and tend to throw the valve 1) rearwardly to the 1 position shown in Figure 2. At about the V 45 time thatthe piston C covers the passage compressed air and the live pressure vfluid passing -through*the passage 'W to the front end of the chamber Hwill then exceed the rearwardly to the position" illustrated in Figure 2. In this position of. the valvethe passage Z will be uncovered by the central head 12 and thus establish communication between the rearward end ofthecylinder and the atmosphere; j I

In the .positionof the valve as illustrated I in Figure 2, the 'port T will be uncovered by the head e and pressure fluid will flow to tained.

the frtint end of the cylinder Al for returning the piston. After the piston G has travelled a sufficient distance to cover the exhaust port B, a portion of the entrapped atmospheric air in-therearward endoi-"the cylinder will pass through the passage Z into the. chamber II, from whence it may pass to the atmosphere through the passage As the piston continues on its rearward travel, the passage Z will be covered. For the remainder of the stroke of the pistonthe airin-the rearward end of the cylinder will'be compressed.and'will act against theactuating face 71. of the valve. After the free exhaust port. B is again uncover-ed by thepi's-I ton C, the pressurefluid in thefront end "of the cylinder A will be .exhaustedtothe atmosphere. The pressure 'fluidl acting against the'actuating face 9 will then drop to a lower value thanthe combinedpressures.

of the live pressure fluid from the passage" X and the compressed atmospheric air which acts against the actuating face hand the valve will again be thrown to the position illustrated in Figure thus completing the cycle of operations.

- By means of this invention the compressed atmospheric air in the ends of the cylinder may be so controlled as to prevent any retarding eflect upon the pistonand a quick and positive valve action may be thus ob Iclaim: 1' I 'w 1. In a rock drill, the combination of a cylinder having a free exhaust port, a re-,

ciprocatory hammer piston in the cylinder controlling said exhaust port, a valve chest having a chamber, said valve chest hav-' ing inlet passages. leading from the ends of said chamber to the ends of the, cylinder, crossed passages leading fromthe ends of' the cylinder to points on opposite sides of the center of the chamber for exhausting a portion of entrappedair from the'cylinder, the remaining entrapped air passing to that end of the chamber corresponding to the end of the cylinder to which the piston is moving, and a-valve having end heads for controlling the admission of pressure fluid through the inlet passages and havlng'a cen-;

tral head alternately covering and uncover ing the-crossed passages, said. outer heads being constantly exposed to live pressure .fluidito augment the entrappedair for actuating'the valve, i i

2., In a rock drill, the combination of K cylinder having a free exhaust port, a '1:-e-.

' ciprocatory hammer piston in thecylinder controlling said exhaust port, a valve chest having-"a chamber, 'admissionports in said chamber in constant comunication. with a' source ofpressure fluid supply, inlet passages l-eading from the ends of the chamber'to the ends of the cylinder, crossed passages leading fromthe ends of the cylinder piston, a reciproc'atory valve in the chamber,

said valve having a central head for alter- ,nately covering and uncovering the crossed passages, and end heads for controlling the admission ports, and passages leading from the admission ports to the ends of the chamber constantly admitting live pressure fluid W to both ends of the valve for actuating the valve. I v In testimony whereof I have signed this specification. 7

GEORGE W. HULSHIZER, 

